1. Field of Invention
The present invention relates to a radio measurement collection method of measuring and collecting a radio environment, and relates also to a radio terminal.
2. Descriptions of Related Art
In case of mobile communication systems, if a building is constructed on the periphery of a radio base station and if the installation situation of the peripheral base stations of the radio base station changes, then the radio environment related to this radio base station changes. Therefore, conventionally, drive tests to measure and collect the radio environment are carried out by an operator using a measurement vehicle which is installed with a measuring instrument.
Although, these types of measurements and collections of the radio environment can contribute to the optimization of parameters of a radio base station, etc., the man-hours involved are large and there is also a problem of high costs. Accordingly, under the 3GPP (3rd Generation Partnership Project) which is a standardization project of the mobile communication systems, the specification plan of MDT (Minimization of Drive Test) is being promoted. MDT is a technology to automate the measurement and collection of radio environments by using the radio terminals which the user has (see 3GPP TR 36.805 V9.0.0 “Study on Minimization of drive-tests in Next Generation Networks”, 2009-12, and 3GPP TS 37.320v0.7.0, “Radio measurement collection for Minimization of Drive Tests (MDT)”, 2010-07).